The World Wide Web (Web) is an ubiquitous communications network used to readily access available resources on many computers throughout the world and is attached to at least one computer network known as the Internet. The Web comprises a body of software, a set of protocols and a set of defined conventions for obtaining information on the Web. The Web utilizes hypertext and multimedia techniques to make the Web "user-friendly" for anyone who desires to browse, roam or contribute to the Web.
A HyperText Transport Protocol (HTTP) is a protocol that is used for transporting hypertext files across the Internet. In ordinary HTTP operation, a proxy receives an HTTP request for a resource and connects to a host identified in a uniform resource locator (URL). A URL is a standardized way of representing different documents, media and network services on the Web. The proxy retrieves the resource and returns a HTTP response to the requester.
In normal HTTP operation, the browser requests a HyperText Markup Language (HTML) response. A HTML is a standardized way to create hypertext documents for use on the Web; HTML is a coding language that surrounds the text used in the hypertext documents with codes and brackets to indicate how the text should appear to the user. When the browser receives the HTML response, the browser parses it and issues individual requests for dependent resources, such as in-line images. Over a narrow-band, high latency connection, this "ping-ponging" (e.g., the browser requesting and receiving each dependent resource individually) results in a severe delay in completing the retrieval of an entire Web page. For a page containing N in-line resources retrieved over a link with an average round-trip latency of L seconds, the delay is approximately ((N+1)*L) seconds.
As a result of delays in delivery of information over narrow-band communications links, there exists a need for a system that delivers information to browser clients over wide-area, narrow-band communications systems in an efficient manner.
A preferred embodiment of the invention, is now described, by way of example only, with reference to the drawings.